scholarly journals Relationships of retained energy and retained protein that influence the determination of cattle requirements of energy and protein using the California Net Energy System

2018 ◽  
Vol 3 (3) ◽  
pp. 1029-1039 ◽  
Author(s):  
Luis O Tedeschi
Keyword(s):  
Body Fat ◽  
Energy System ◽  
The Body ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Body Protein ◽  
Protein Requirements ◽  
Growing Cattle ◽  
Lower Correlation

Abstract Interrelationships between retained energy (RE) and retained protein (RP) that are essential in determining the efficiency of use of feeds and the assessment of energy and protein requirements of growing cattle were analyzed. Two concerns were identified. The first concern was the conundrum of a satisfactory correlation between observed and predicted RE (r = 0.93) or between observed and predicted RP when using predicted RE to estimate RP (r = 0.939), but a much lower correlation between observed and predicted RP when using observed RE to estimate RP (r = 0.679). The higher correlation when using predicted vs. observed RE is a concern because it indicates an interdependency between predicted RP and predicted RE that is needed to predict RP with a higher precision. These internal offsetting errors create an apparent overall adequacy of nutrition modeling that is elusive, thus potentially destabilizing the predictability of nutrition models when submodels are changed independently. In part, the unsatisfactory prediction of RP from observed RE might be related to the fact that body fat has a caloric value that is 1.65 times greater than body protein and the body deposition of fat increases exponentially as an animal matures, whereas body deposition of protein tends to plateau. Thus, body fat is more influential than body protein in determining RE, and inaccuracies in measuring body protein will be reflected in the RP comparison but suppressed in the RE calculation. The second concern is related to the disconnection when predicting partial efficiency of use of metabolizable energy for growth (kG) using the proportion of RE deposited as protein—carcass approach—vs. using the concentration of metabolizable energy of the diet—diet approach. The culprit of this disconnection might be related to how energy losses that are associated with supporting energy-expending processes (HiEv) are allocated between these approaches. When computing kG, the diet approach likely assigns the HiEv to the RE pool, whereas the carcass approach ignores the HiEV, assigning it to the overall heat production that is used to support the tissue metabolism. Opportunities exist for improving the California Net Energy System regarding the relationships of RE and RP in computing the requirements for energy and protein by growing cattle, but procedural changes might be needed such as increased accuracy in the determination of body composition and better partitioning of energy.

scholarly journals 351 Awardee Talk: How retained energy and protein affects the determination of energy and protein requirements for growth

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 84-85
Author(s):  
Luis O Tedeschi
Keyword(s):  
Body Composition ◽  
Nutritive Value ◽  
The Body ◽  
Metabolizable Energy ◽  
Protein Requirements ◽  
Body Tissues ◽  
Methodological Procedures ◽  
Areas Of Concern ◽  
Maintenance Requirements

Abstract The understanding of how nutrition influences the body composition of growing animals has fascinated researchers for centuries. It involves the expertise of scientists with different areas of knowledge, encompassing the composition of the diet and its nutritive value to the fermentation and digestion of substrates to the absorption and metabolism of nutrients, and finally, to the deposition of fat, protein, and minerals in body tissues. The comparative slaughter technique is the preferred method to assess the body composition of growing and finishing animals. However, the methodological procedures are labor-intensive, expensive, and time-consuming, facilitating the incidence of errors and inconsistencies of the measurements that are collected, including the initial animal’s body composition. First, retained fat and protein (RP) are used to compute retained energy (RE). Then, RP and RE are used to compute protein and energy requirements for growth. Heat production, calculated from the metabolizable energy (ME) intake for animals at maintenance, is used to compute maintenance requirements. Three areas of concern exist for this approach: 1) the efficiencies of possible mobilization of fat and protein tissues during the feeding period are unaccounted for, especially for the animals fed near the maintenance level of intake; 2) the correlation between observed and predicted RP when using predicted RE is higher than when using observed RE (0.939 vs. 0.679); and 3) the disconnection when predicting partial efficiency of use of ME for growth using the proportion of RE deposited as protein — carcass approach — versus using the concentration of ME of the diet — diet approach. These concerns raised questions about the interdependency between predicted RP and RE and the existence of internal offsetting errors that may prevent overall adequacy in predicting energy and protein requirements of beef cattle.

scholarly journals Energy and protein requirements of crossbred cattle in feedlot

2016 ◽  
Vol 37 (2) ◽  
pp. 1029 ◽  
Author(s):  
Maria Luciana Menezes Wanderley Neves ◽  
Antonia Sherlânea Chaves Véras ◽  
Evaristo Jorge Oliveira de Souza ◽  
Marcelo De Andrade Ferreira ◽  
Sebastião De Campos Valadares Filho ◽  
...  
Keyword(s):  
Body Weight ◽  
Reference Group ◽  
The Body ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Adaptation Period ◽  
Protein Requirements ◽  
Randomized Design ◽  
Dairy Bulls ◽  
Slaughter Method

The objective of this study is to predict the energy and protein requirements of crossbred dairy cattle in feedlot. The study was conducted at the Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, Brazil with 30 bulls with a body weight of 339.1 ± 35.4 kg. Five animals were slaughtered at the end of the adaptation period to serve as the reference group; the remainder of the animals was slaughtered after 112 days. The latter group was randomly allocated to receive five treatments: 0, 17, 34, 51 and 68% of concentrate in the feed using a completely randomized design. The dietary intake of the animals that were not given concentrate was restricted to 1.5% of their body weight; these animals composed the group fed for maintenance. The body composition and empty body weight (EBW) were estimated by means of the comparative slaughter method and full dissection of a half-carcass. The results showed that for crossbred dairy bulls in confinement, the net and metabolizable energy requirements were 86.49 and 138 kcal EBW-0.75 day-1, respectively, and the efficiency of use of metabolizable energy for maintenance and gain were 62.67% and 31.67%, respectively. The net energy (NEg) and net protein (NPg) requirements for gain can be estimated using the following equations, respectively: NEg= 0.0392*EBW0.75*EBWG1.0529 and NPg= 242.34 x EBWG - 23.09 x RE. The efficiency of use of metabolizable protein for gain was 25.8%, and the protein requirement for maintenance was 2.96 g EBW-0.75 day-1. The rumen degradable protein can supply 62.44% of the crude protein requirements of feedlot dairy crossbred bulls with a body weight of 450 kg while gaining 1 kg day-1.

A new net energy system for ruminants

1974 ◽  
Vol 19 (2) ◽  
pp. 141-148 ◽  
Author(s):  
J. Harkins ◽  
R. A. Edwards ◽  
P. Mcdonald
Keyword(s):  
Linear Programming ◽  
Research Council ◽  
Agricultural Research ◽  
Energy System ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Iterative Approach ◽  
Agricultural Research Council ◽  
Growing Cattle

SUMMARYA simplified Net Energy system for ruminants is described. It is based on the Metabolizable Energy system outlined by the Agricultural Research Council (1965) and enables a non-iterative approach to be used in the formulation of rations. The method is suitable for use in linear programming work and is illustrated, with appropriate tables, for growing cattle.

scholarly journals Energy and protein requirements of crossbred Holstein x Zebu steers fed different levels of calcium and phosphorus in the diet

2016 ◽  
Vol 37 (4Supl1) ◽  
pp. 2665
Author(s):  
Diego Zanetti ◽  
Sebastião De Campos Valadares Filho ◽  
Edenio Detmann ◽  
Marcos Vinicius Carneiro Pacheco ◽  
Letícia Artuzo Godoi ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Weight Gain ◽  
The Body ◽  
Metabolizable Energy ◽  
Dicalcium Phosphate ◽  
Energy Requirements ◽  
Net Energy ◽  
Protein Requirements ◽  
Two Samples ◽  
Net Protein

The aim of this study was to determine the energy and protein requirements of crossbred Holstein x Zebu steers fed with or without the supplementation of dicalcium phosphate in the diet. Thirty-two steers with an average initial body weight of 377.5 ± 49.4 kg were used, of which four were initially slaughtered to estimate the empty body weight (EBW) of the animals. Twenty-four steers were fed ad libitum and were distributed in a completely randomized design with two levels of concentrate (30 and 60 %), and diets with or without dicalcium phosphate and four steers were fed at maintenance level, so that the body weight gain was equal to zero. After 84 days the animals were slaughtered. The animal tissues were sampled, and composted by two samples, denominated by “carcass” (bone, muscle and fat) and “non-carcass” (head, limbs, blood, hide, organs and viscera) for determination of the body composition. The net energy requirements (NEm) and metabolizable energy for maintenance (MEm) were obtained while relating heat production (HP) and metabolizable energy intake (MEI); meanwhile, the net energy requirements for gain (NEg) and the net protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW), empty body gain (EBG) and retained energy (RE) in EBW. The daily net and metabolizable energy requirements for maintenance were 76.90 and 119.36 kcal/EBW0.75, respectively. The net energy requirements for gain can be obtained by the following equation: NEg = 0.0568±0.0025 × EBW0.75 × EBG1.095. The efficiencies of use of metabolizable energy for maintenance and gain are 64.4 and 29.68 %, respectively. The metabolizable protein requirements for maintenance are 4.14 g/BW0.75. The net protein requirements for gain can be obtained through the following equation: NPg = 236.36±30.06 × EBG - 19.84±6.14 × RE. We recommend the use of the equations obtained in this experiment to calculate the energy and protein requirements of crossbred Holstein x Zebu steers.

scholarly journals Prediction of the <i>in vivo</i> Body Composition of Pigs Based on Cross- Sectional Region Analysis of Dual Energy X-Ray Absorptiometry (DXA) Scans

2002 ◽  
Vol 45 (6) ◽  
pp. 535-545
Author(s):  
A. D. Mitchell ◽  
A. Scholz ◽  
V. Pursel
Keyword(s):  
Body Composition ◽  
Chemical Analysis ◽  
Body Fat ◽  
The Body ◽  
Cross Sectional ◽  
Body Protein ◽  
Total Body Fat ◽  
Total Body ◽  
Dxa Scans

Abstract. The purpose of this study was to evaluate the use of a cross-sectional scan as an alternative to the total body DXA scan for predicting the body composition of pigs in vivo. A total of 212 pigs (56 to 138 kg live body weight) were scanned by DXA. The DXA scans were analyzed for percentage fat and lean in the total body and in 14 cross-sections (57.6 mm wide): 5 in the front leg/thoracic region, 4 in the abdominal region, and 5 in the back leg region. Regression analysis was used to compare total body and cross-sectional DXA results and chemical analysis of total body fat, protein and water. The relation (R2) between the percentage fat in individual slices and the percentage of total body fat measured by DXA ranged from 0.78 to 0.97 and by chemical analysis from 0.71 to 0.85, respectively. The relation between the percentage of lean in the individual slices and chemical analysis for percentage of total body protein and water ranged from 0.48 to 0.60 and 0.56 to 0.76, respectively. These results indicate that total body composition of the pig can be predicted (accurately) by performing a time-saving single-pass cross-sectional scan.

Seasonal change in feed intake, body composition, and metabolic rate of white-tailed deer

1995 ◽  
Vol 73 (3) ◽  
pp. 452-457 ◽  
Author(s):  
Karol A. Worden ◽  
Peter J. Pekins
Keyword(s):  
Body Composition ◽  
Metabolic Rate ◽  
Body Fat ◽  
Feed Intake ◽  
Deuterium Oxide ◽  
Critical Time ◽  
Metabolizable Energy ◽  
Body Protein ◽  
Daily Energy ◽  
Time Of Year

Winter is a critical time of year for white-tailed deer (Odocoileus virginianus) in northern regions because their food consumption does not meet their daily energy demands. We measured feed intake, fasting metabolic rate (FMR), and body composition of five captive adult female white-tailed deer from September 1991 through March 1992 in New Hampshire to investigate the relationships between FMR and feed intake to fat deposition and mobilization. Deuterium oxide dilution was used to estimate monthly body composition, indirect respiration calorimetry was used to measure monthly FMR, and metabolizable energy intake (MEI) was calculated from daily feed intake. Mean percent body fat increased from 9.1 ± 1.5 to 24.9 ± 4.4% from September to December, and then declined through March. Mean percent body protein did not change during the study (range 20–21%). Mean MEI peaked during September and October (171.9 ± 8.1 and 168.7 ± 10.3 kcal∙kg body mass−0.75∙d−1, respectively), and declined 54% by February. Mean FMR ranged from 79 to 90 from October through March. Correlations between MEI or FMR and change in body fat were weak. It was estimated that intake rates of free-ranging deer were only 90–110% of winter FMR, and that deer with 20% body fat could balance their daily energy expenditure (1.7 × FMR) with fat stores for about 3 months, or the period of time during which MEI was depressed in captive deer.

scholarly journals How did Lofgreen and Garrett do the math?

2019 ◽  
Vol 3 (3) ◽  
pp. 1011-1017
Author(s):  
James W Oltjen
Keyword(s):  
Body Weight ◽  
Energy Content ◽  
Energy System ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Significant Difference ◽  
Linear Fit ◽  
Metabolizable Energy Intake ◽  
Logarithmic Equation ◽  
Finishing Beef Cattle

Abstract Lofgreen and Garrett introduced a new system for predicting growing and finishing beef cattle energy requirements and feed values using net energy concepts. Based on data from comparative slaughter experiments they mathematically derived the California Net Energy System. Scaling values to body weight to the ¾ power, they summarized metabolizable energy intake (ME), energy retained (energy balance [EB]), and heat production (HP) data. They regressed the logarithm of HP on ME and extended the line to zero intake, and estimated fasting HP at 0.077 Mcal/kg0.75, similar to previous estimates. They found no significant difference in fasting HP between steers and heifers. Above maintenance, however, a logarithmic fit of EB on ME does not allow for increased EB once ME is greater than 340 kcal/kg0.75, or about three times maintenance intake. So based on their previous work, they used a linear fit so that partial efficiency of gain above maintenance was constant for a given feed. They show that with increasing roughage level efficiency of gain (slope) decreases, consistent with increasing efficiency of gain and maintenance with greater metabolizable energy of the feed. Making the system useful required that gain in body weight be related to EB. They settled on a parabolic equation, with significant differences between steers and heifers. Lofgreen and Garrett also used data from a number of experiments to relate ME and EB to estimate the ME required for maintenance (ME = HP) and then related the amount of feed that provided that amount of ME to the metabolizable energy content of the feed (MEc), resulting in a logarithmic equation. Then they related that amount of feed to the net energy for gain calculated as the slope of the EB line when regressed against feed intake. Combining the two equations, they estimate the net energy for maintenance and gain per unit feed (Mcal/kg dry matter) as a function of MEc: 0.4258 × 1.663MEc and 2.544–5.670 × 0.6012MEc, respectively. Finally, they show how to calculate net energy for maintenance and gain from experiments where two levels of a ration are fed and EB measured, where one level is fed and a metabolism trial is conducted, or when just a metabolism trial is conducted—but results are not consistent between designs.

Estimation of body water and fat in cattle using tritiated water space and live weight with particular reference to the influence of breed

1983 ◽  
Vol 101 (2) ◽  
pp. 257-264 ◽  
Author(s):  
P. R. N. Chigaru ◽  
D. H. Holness
Keyword(s):  
Body Fat ◽  
Total Body Water ◽  
Tritiated Water ◽  
Live Weight ◽  
Close Relation ◽  
Body Water ◽  
The Body ◽  
Metabolizable Energy ◽  
Complete Diet ◽  
Total Body

SUMMARYThe body composition of 18 each of Mashona, Afrikaner and Hereford heifers was measured at the beginning and after 16 and 32 weeks of the experiment. The heifers not slaughtered at the beginning of the experiment were fed a complete diet containing 132 g crude protein and 12·0 MJ metabolizable energy/kg dry matter. Before slaughter, the animals were deprived of food and water for 24 h. Each animal was infused with 1 mCi of tritiated water (TOH) in order to measure total body water (TBW) and to estimate body fat.The growth rate of the three breeds of heifers was similar despite differences in age and initial live weight. Both TBW and fat proportions, however, differed significantly (P < 0·01) between slaughter stages for each breed and between breeds at each slaughter stage. At the first, second and final slaughter stages the proportions of TBW were: 68·0, 59·4 and 54·5% for Mashona; 70·;5, 64·3 and 58·3% for Afrikaner and 65·3, 57·6 and 46·2% for Hereford heifers respectively. The corresponding proportions of body fat were: 10·2, 18·4 and 24·2% for Mashona; 6·6, 12·0 and 20·0% for Afrikaner and 13·7, 20·8 and 25·8% for Hereford heifers respectively.There was a close relation between empty body weight and live weight at slaughter which was not influenced by breed. Both TBW and fat were estimated more accurately when TOH space and live weight were used jointly. However, the slopes of the prediction equations for each breed were significantly different (P < 0·05) in the case of both total body water and fat. It was necessary to use separate equations for each breed in order to predict either body water or fat. The significance of these findings for the estimation of body fat in live cattle is discussed.

Mofification of body composition by clenbuterol in normal and dystrophic (mdx) mice

1985 ◽  
Vol 5 (9) ◽  
pp. 755-760 ◽  
Author(s):  
Nancy J. Rothwell ◽  
Michael J. Stock
Keyword(s):  
Body Composition ◽  
Body Fat ◽  
Fat Body ◽  
Energy Content ◽  
The Body ◽  
Mdx Mice ◽  
Body Protein ◽  
Lower Protein ◽  
Dystrophic Mice ◽  
Β2 Agonist

Female dystrophic mice (mdx on C57 Black background) gained weight more rapidly than age-matched controls and had a higher body fat content (% body weight), a slightly lower protein content and a reduced mass of muscle. Chronic treatment (21 d) of the mice with the β2-agonist clenbuterol stimulated weight gain in both genotypes without affecting energy intake. Clenbuterol increased the mass of the gastrocnemius and soleus muscle by 13% and 29% in normal and dystrophic mice, respectively, and raised body protein but depressed body fat. Body water and energy content were unaffected by clenbuterol, but the ratio of protein to fat in the carcasses was enhanced by 17% in normal and 56% in dystrophic mice following clenbuterol treatment. Thus, the β2-agonist restored the body composition of dystrophic mice to normal and enhanced the protein to fat ratio in both these and normal mice.

THE GROSS BODY COMPOSITION OF SIX GEOGRAPHIC RACES OF PEROMYSCUS

1965 ◽  
Vol 43 (2) ◽  
pp. 297-308 ◽  
Author(s):  
J. S. Hayward
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Body Fat ◽  
Comparative Studies ◽  
The Body ◽  
Deer Mice ◽  
Body Protein ◽  
Free Body ◽  
Laboratory Acclimation ◽  
Seasonal Extremes

The body composition in terms of fat, water, and protein has been determined for 115 deer mice (genus Peromyscus) of six racial stocks. The changes in composition that are characteristic of seasonal extremes and that accompany laboratory acclimation are presented. The composition of the fat-free body exhibits the constancy which has been found in other mammals. Body protein averaged 22.97% and body water 69.71% of the fat-free body weight. Body fat levels are shown to vary considerably among individuals and races. The highest fat levels occurred in the desert-adapted race (P. m. sonoriensis). The importance of considering body composition in comparative studies of metabolic rate is discussed.

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